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.TH thin_migrate 8 "Device Mapper Tools" "System Manager's Manual"
.SH NAME
\fBthin_migrate
\fB
.SH SYNOPSIS
.nf
.fam C
\fBthin_migrate\fP [\fIoptions\fP] \fB--source-dev\fP {device} \fB--dest-dev\fP {device}
\fBthin_migrate\fP [\fIoptions\fP] \fB--source-dev\fP {device} \fB--dest-file\fP {file}

.fam T
.fi
.fam T
.fi
.SH DESCRIPTION
\fBthin_migrate\fP copies provisioned data blocks from a thin device to another
device or file. It is designed for cloning a read-only snapshot or thin
volume within a live thin-pool. A metadata snapshot is required to read the
data mappings.
.SH OPTIONS
.TP
.B
\fB-h\fP, \fB--help\fP
Print help and exit.
.TP
.B
\fB-V\fP, \fB--version\fP
Print version information and exit.
.TP
.B
\fB--source-dev\fP {device}
The input read-only thin device to copy.
.TP
.B
\fB--dest-dev\fP {device}
The output device as the copy destination.
.TP
.B
\fB--dest-file\fP {file}
The output file as the copy destination.
.TP
.B
\fB-q\fP, \fB--quit\fP
Suppress output messages, return only exit code.
.TP
.B
\fB--buffer-size-meg\fP {size}
Specify the size of the data buffers, in megabytes.
.SH EXAMPLE

Assuming that there's a thin snapshot 'vg/snap' to copy, we must first set
the snapshot to read-only:
.PP
.nf
.fam C
    $ lvchange vg/snap --permission r

.fam T
.fi
Next, create a metadata snapshot for running \fBthin_migrate\fP:
.PP
.nf
.fam C
    $ dmsetup message vg-mythinpool-tpool 0 reserve_metadata_snap

.fam T
.fi
Once the metadata snapshot is created, copy the snapshot into another linear
or thin volume. The destination volume must have the same size as the source
device.
.PP
.nf
.fam C
    $ thin_migrate --src-device /dev/vg/snap --dest-device /dev/vg2/dest

.fam T
.fi
Alternatively, copy the snapshot into a file. \fBthin_migrate\fP can optionally
create the destination file if it is not present, or the size of the file
will be truncated to match that of the source device.
.PP
.nf
.fam C
    $ thin_migrate --src-device /dev/vg/snap --dest-file dest.bin

.fam T
.fi
Finally, release the metadata snapshot after \fBthin_migrate\fP finishes its job:
.PP
.nf
.fam C
    $ dmsetup message vg-mythinpool-tpool 0 release_metadata_snap

.fam T
.fi
.SH DIAGNOSTICS
\fBthin_migrate\fP returns an exit code of 0 for success or 1 for error.
.SH AUTHOR
Joe Thornber <ejt@redhat.com>